错误：在Xcode中使用未声明的标识符NSOpenPanel

Question

I'm getting the following error:

Use of undeclared identifier NSOpenPanel

NSOpenPanel *panel = [NSOpenPanel openPanel];
[panel setCanChooseFiles:NO];
[panel setCanChooseDirectories:YES];
[panel setAllowsMultipleSelection:YES]; // yes if more than one dir is allowed 
NSInteger clicked = [panel runModal];
if (clicked == NSFileHandlingPanelOKButton) 
{
    for (NSURL *url in [panel URLs]) 
    {
        // do something with the url here.
    }
}

Answer 1

NSOpenPanel is not available in iOS , only under macOS ( Cocoa ).

You can not let the user browse the file system under iOS . You can browse certain file types though, using Apples public API. For instance you can let the user choose images using UIImagePickerController